Method of braking internal-combustion motors.



W. SCHWERDIFEGER. METHOD OF BRAKING INTERNAL COMBUSTION MOTORS.

APPLICATION FILED JULY 31. I915.

Patented Nov. 16, 1915.

ex/mmsz stroke suction stroke cram/6 06m cmyaressa'a/r aim wzwemfw" WALTER SCHWERDTFEGER, F STUTTGART-UNTERTURKHEIM, GERMANY, ASSIGNOJR- TO DAIMLER-MOTOREN-GESELLSCHAFT, OF UNTERTTTRKHEIM, GERMANY, A COR- PORATION 0F GERMANY.

METHOD OF BRAKING INTERNAL-COMBUSTION MOTORS.

Specification of Letters Patent. I Pate ted N 116 19115 Application filed July 31, 1915. Serial No. 42,994.

' rncnn, subject of the Emperor of Germany,

residing at 24 B. Panoramastrasse, Stuttgart-Untertiirkheim, Germany, have invented certain new and useful Improvements in Methods of Braking Internal-Combustion Motors, of which the following is a specification.

This invention relates to a method of braking internal combustion motors of the two, four or six-stroke cycle type by aid of the motor itself.

According to the invention, in order to increase the braking effect, instead of the air contained in the cylinder, the fuel-aim mixture contained therein is compressed after ignition and is then expelled.

In the drawing'afiixed to this specification the method according to the present invention is illustrated diagrammatically as applied to a vertical four-stroke cycle motor. The spiral surrounding the crank circle is intended to diagrammatically indicate the four strokes of the piston when my improved method is in operation.

First str0kc.--The piston passes from the upper part of the cylinder to the outer dead center and draws in a mixture of fuel and air.

Second stroke.-The suction period ends in the outer dead center or somewhat later,

as usual. Shortly after it is ended the explosive mixture in the cylinder is ignited, either by adjusting the ignition device provided for the normal service of the motor or by aid of a specially provided ignition device thrown in, whenever the motor is to be braked. According to the quantity of mixture, which can be varied in order to regulate the braking power, an increase of pressure will take place within the cylinder. The piston ascending during this time thereby suffers a higher resistance than with compressed air or non-ignited mixture, the resistance increasing, as the piston proceeds on its upward course, on account of the compressed gases being ignited. As soon as the piston has reached the inner dead center, or has come near it, the exhaust valve is opened, a special device such as a displaceable cam shaft or displaceable cams bemg required for this purpose, as the motion of the exhaust valve, during the braklng period, differs-from the normal motion during the regular service. of the'motor as a power engine. As soon as the exhaust is opened the compressed gases escape and the pressure becomes normal.

Third st1=07ce.-Preferably the exhaust remains opened all through the third stroke, thus allowing a full equalization of the pressure in the cylinder to that of the air to take place.

Fourth stroke-Also during the fourth stroke, while the piston is passing from the outer to the inner dead center, the exhaust valve remains open, thus allowing the exhaust gases in the cylinder to be expelled.

The exhaust valve remains open until the suction period begins (first stroke).

The braking effect can be regulated, as mentioned before, by varying the quantity of mixture admitted into the cylinder or else by varying the time or the extent of opening of the exhaust valve. Instead of the exhaust valve a special valve may be provided for expelling the compressed and ignited gases.

1. The method of braking internal combustion motors which consists in igniting the explosive mixture in the cylindar im mediately after a suction stroke has been completed by the piston, permitting the compressed gases to escape from the cylinder at approximately the end of the compression stroke immediately following and continuing the escape of said gases during the entire next succeeding stroke of the piston.

2. The method of braking internal combustion motors which consists inigniting the explosive mixture in the cylinder immediately after a suction stroke has been completed by the piston, permitting the compressed gases to escape from the cylinder at approximately the end of the compression stroke immediately following and continuthereof and means for exhausting the exing the escape of said gases during the next plosion gases at approximately the end of tWo succeeding strokes of the piston. the compression strokes and during succeed- 10 3. In an internal combustion motor, the ing strokes'of the piston. 5 combination of a cylinder, means for com- In testimony whereof I afiix my signature.

pressing an explosive mixture therein, means for igniting the mixture before compression WALTER SCHWERDTFEGER.

Copies of this patent may be obtained for five cents each, by addressing the Commissioner of Patents. Washington, D. 0. 

